Les sols de savanes des llanos vénézuéliens et le sol ferrugineux tropical de Barinas = Los suelos de sabanas de los llanos venezolanos y el alfisol de Barinas

Les savanes constituent une des dernières ressources en terres dont la mise en culture est relativement facile malgré de faibles réserves organiques et minérales qui ne leur assurent qu'un équilibre assez fragile. La station expérimentale du Jardin botanique de l'université expérimentale des Llanos à Barinas sert de cadre depuis 1977 à des expériences effectuées sur un sol ferrugineux tropical lessivé. Le présent travail est consacré à la description : du contexte régional de la station; du profil du sol utilisé en comparaison avec d'autres sols de savanes; de quelques résultats obtenus dans la station et dans la région sur des types de sol voisins. Avant de conclure est discutée la représentativité de la station de Barinas au niveau des savanes en général en vue d'établir la portée des expériences qui y sont ou y seront effectuées. (Résumé d'auteur

What is the duration of untreated psychosis worldwide? - A meta-analysis of pooled mean and median time and regional trends and other correlates across 369 studies.

Duration of untreated psychosis (DUP) has been associated with poor mental health outcomes. We aimed to meta-analytically estimate the mean and median DUP worldwide, evaluating also the influence of several moderating factors. This PRISMA/MOOSE-compliant meta-analysis searched for non-overlapping individual studies from inception until 9/12/2022, reporting mean ± s.d. or median DUP in patients with first episode psychosis (FEP), without language restrictions. We conducted random-effect meta-analyses, stratified analyses, heterogeneity analyses, meta-regression analyses, and quality assessment (PROSPERO:CRD42020163640). From 12 461 citations, 369 studies were included. The mean DUP was 42.6 weeks (95% confidence interval (CI) 40.6-44.6, k = 283, n = 41 320), varying significantly across continents (p < 0.001). DUP was (in descending order) 70.0 weeks (95% CI 51.6-88.4, k = 11, n = 1508) in Africa; 48.8 weeks (95% CI 43.8-53.9, k = 73, n = 12 223) in Asia; 48.7 weeks (95% CI 43.0-54.4, k = 36, n = 5838) in North America; 38.6 weeks (95% CI 36.0-41.3, k = 145, n = 19 389) in Europe; 34.9 weeks (95% CI 23.0-46.9, k = 11, n = 1159) in South America and 28.0 weeks (95% CI 20.9-35.0, k = 6, n = 1203) in Australasia. There were differences depending on the income of countries: DUP was 48.4 weeks (95% CI 43.0-48.4, k = 58, n = 5635) in middle-low income countries and 41.2 weeks (95% CI 39.0-43.4, k = 222, n = 35 685) in high income countries. Longer DUP was significantly associated with older age (β = 0.836, p < 0.001), older publication year (β = 0.404, p = 0.038) and higher proportion of non-White FEP patients (β = 0.232, p < 0.001). Median DUP was 14 weeks (Interquartile range = 8.8-28.0, k = 206, n = 37 215). In conclusion, DUP is high throughout the world, with marked variation. Efforts to identify and intervene sooner in patients with FEP, and to promote global mental health and access to early intervention services (EIS) are critical, especially in developing countries

Update of the PANCCO clinical practice guidelines for the treatment of ulcerative colitis in the adult population

Ulcerative colitis (US) is a chronic disease of unknown etiology. It is incurable and its clinical course is intermittent, characterized by periods of remission and relapse. The prevalence and incidence of the disease has been increasing worldwide. The update presented herein includes the participation of healthcare professionals, decision-makers, and a representative of the patients, all of whom declared their conflicts of interest. Answerable clinical questions were formulated, and the outcomes were graded. The information search was conducted on the Medline/PubMed, Embase, Epistemonikos, and LILACS databases, and covered grey literature sources, as well. The search was updated on November 30, 2020, with no restrictions regarding date or language. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) classification system was implemented to establish the strength of the recommendation and quality of evidence. A formal consensus was developed, based on the RAND/UCLA methodology and the document was peer reviewed. The short version of the Clinical Practice Guidelines for the Treatment of Ulcerative Colitis in the Adult Population is presented herein, together with the supporting evidence and respective recommendations. In mild-to-moderate UC, budesonide MMX is an option when treatment with 5-ASA fails, and before using systemic steroids. In moderate-to-severe UC, infliximab, adalimumab, vedolizumab, ustekinumab, and tofacitinib can be used as first-line therapy. If there is anti-TNF therapy failure, ustekinumab and tofacitinib provide the best results. In patients with antibiotic-refractory pouchitis, anti-TNFs are the treatment of choice

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

Design concepts for the Cherenkov Telescope Array CTA: an advanced facility for ground-based high-energy gamma-ray astronomy

Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA

Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)